Four drown in tour boat accident in Ottawa

A tour boat sank on the Ottawa River within sight of Canada's Parliament and four of its passengers drowned, including a mother and her two children.

The boat sank near a dock on Sunday and rescuers could not save four of the 10 passengers and two crew members on board, police said.

"When it sank, all the people on board went under water," Yves Martel of the Gatineau police said. "It seemed that it sank quite rapidly."

The cause of the accident is not yet known and the passengers appeared to be wearing lifejackets.